OFDM系统中基于匹配追踪的稀疏信道估计算法研究

Study on sparse channel estimation algorithm based on matching pursuit for OFDM systems

针对OFDM系统,利用信道冲激响应的稀疏特性,提出了一种新的OFDM稀疏信道估计算法。它分两步完成:首先利用匹配追踪思想确定出非零抽头系数的位置,然后再采用最小二乘算法完成对非零系数值的二次估计,从而通过减少信道估计参数的个数降低算法复杂度。该算法具有较好的归一化均方误差性能,但在剩余向量更新上还不是很精确,通过改进剩余向量的更新方式,得到了另一种性能更优的OFDM-MMP算法。仿真结果验证了该算法的有效性。

A novel OFDM channel estimation algorithm is proposed by exploiting the sparsity of channel impulse response. Firstly, the matching pursuit idea was used to detect the position of the nonzero tap coefficients; secondly the least square algorithm was utilized to estimate the exact value of the nonzero coefficients, and thus to reduce the computational complexity of the algorithm by decreasing the numbers of the channel parameters being estimated. This algorithm has good NMSE performance, but the update of the residue vector is not exact. Hence, another algorithm called OFDM-MMP which has better performance is acquired by modifying the mode of the residue vector update. Simulation results demonstrate the validity of the algorithm.